Strange garden boundary observation/WWYD? - pics (sort of)

Rural_Puppy

What sort of hedge is it? Privet? Something spikey? Something invasive? I think the hedge might be the least of your worries, if the neighbours are as batty as this!

MoneySeeker1

Definite No! to "leaning over and spraying Round-up".

They will not be happy with that idea - unless they use loads of chemicals themselves. You have to start from the assumption they don't use chemicals - and, even if those particular house occupants do use chemicals - they might sell the house on at some point to someone else that doesn't use them and you've only delayed the resulting row about it.

getmore4less

if they are happy to let you fix the hedge a couple of options.

SImple but a bit untidy, cut it down a bit over the fence and cover with light proof sheeting it will die back over time.

if it is wide enough between the fences cut back a bit big enough to get into the hedge area.
(if your fence panels are easy to remove that may be easier even if every other one)

Cut it all down then grub out the roots with a mattock
Level and cover the ground with membrane upto and just under the fences, wrapped under  gravel boards would be one option,
hold down with something, stuff will grow in most options eventually
Anything organic like bark will breakdown and stuff grows sooner and more vigorously, it is from seeds falling onto it not through whats down.
 
A light covering of gravel would be easy and cheap and probably get very light growth for a few years 

silvercar

This is their hedge in their garden. I would either:
a) remove your own fence and use their hedge as the boundary, keeping the side that is your garden well trimmed. Occasionally offer to top the hedge for your neighbours when the height gets too intrusive.
b) keep the fence up and ignore what your neighbours are doing in their own garden. Again lop off anything that grows over your side.